Neutron Scattering at 4.5 GPa and 20 K

Abstract

Although the pressure variable is of fundamental physical importance, the technology to use high pressures in elastic neutron scattering experiments above pressures of 1 GPa only became available about 1970, and the first inelastic neutron scattering experiments in this pressure range were done in 1975. Presently, samples of about 1/4 cc can be studied from 1 atm to 4.5 GPa at temperatures from 20 K to room temperature. The relatively small sample volume is the fundamental limitation to the types of inelastic neutron scattering experiments which can be done with currently available neutron sources. It is possible to study the effect of pressure on phonons and crystal field levels up to energy transfers of the order of 10 MeV, and this is sufficient for a number of important problems.